You can manually adjust the iTunes equalizer and then save your customized equalizer settings to create your own â€œpresetâ€ to use again. For example, you could create presets for different rooms in your house or different genres of music.
To customize equalizer settings:
Choose ViewÂ > Show Equalizer.
Position the sliders to the desired frequency settings.
Choose Make Preset from the pop-up menu and then name your preset.
To rename or delete a preset, chose Edit List from the pop-up menu.